Liner for oil wells



1,620,412 March 8 1927. J, 'rwEEDDALE LINER FOR oIL WELLS Filed July 30.1925 2 Sheets-Sheet 1 cfa/1x2 f1/'mediale Mar vh 8 1927.

c v J. TWEEDDALE LINER FOR OIL WELLS Filed July 50. 1925 2 Sheets-Sheet2 .m e 9 Z 9 m W Jaw 3 d 6 5 D 5 r. o J 7. 7. 0 7 .3 6 9 9 KVMMqV/' f Al n l ls Patented Mar. 8, 1927.

UNITED STATES JOI-IN TWEEDDALE, OF TORRAN'CE, CALIFORNIA.

LNER FOR OIL WELLS.

Application filed July 30, 1925.

This invention relates to oil well liners which at the present timeconsists merely of a string of pipes provided with oil inflow openingsand which are set in the oil forf mation of oil wells primarily for thepurpose of preventing the caving in of the walls of the wells. The gaspressure in the average well is suiicient to cause the oil, filled withparticles of sharp sand, to spray through the liner openings with greatforce.

The liner openings are 0fradually increased in size by reason of thecontact of the sand with the walls thereof, and in time they areincreased to such size that the liner is so weakened as to collapseunder the pressure thereon. ln addition to enlarging the liner openings,the sand gradually fills up the lower portion of the liner and the gaspressure below this sand forces the same upwardly in the liner with theresult that a bridge is formed which shuts olf the flow 'of oil.

The primary object lof my invention is Vthe provision ofan oil wellliner which cannot be weakened in the manner stated and in which a sandbridge cannot be formed.

The foregoing and other objects are at tained by the construction,combination and arrangement of parts hereinafter fully described andclaimed, and illustrated' in the accompanying drawings, wherein: y

Figure 1 is a View partly in elevation and partly in vertical section ofmy improved liner and the lower end of an oil well casing, the linerbeing in elevation and the casing in section;

Figure 2 is a sectional view illustrating the construction of the headof the liner, the section being taken on the plane indicated by the line2-2 of Figure l;

Figure 3 is a top plan view of the head of the liner;

Figure 4; is a view in side elevation of one of the units of the liner;

Figure 5 is a sectional view taken `on the plane indicated by the line5-5 1of Figure l;

Figure 6 is a view in side elevation of the inner pipe 0f the linerunits, and

Figure 7 is a sectional view taken on the plane indicated by Athe line 77 of Figure 5.

Corresponding and like parts are referred' to in the followingdescription, and designated in the several views of the accom- SerialNo. 47,079.

panying drawings, by similar reference numerals.

rlhe liner comprises sections or units 1, and each unit comprises aninner pipe 2 and an outer' pipe 3. rlhe lower half of the inner pipe 2 sprovided with openings 4, and the upper half of the outer pipe 3 isprovided with openings 5. As the openings a in the pipe 2 do not olfsetthe openings 5 in the pipe 3, the oil entering the pipe 3 cannot passdirectly into the pipe 2 but must hrst pass downwardly between the pipes2 and 3 before entering the pipe 2, and due thereto the oil cannot flowthrough the openings at suoli a high velocity that the sand carriedthereby will enlarge the openings. lt will therefore be apparent thatthe liner will not collapse under the pressure thereon. The openings 4and 5 may be as shown in the drawings of elongated formation andarranged at an angle with respect to the axis of the liner.

The openings 4 and 5 are made at an angle to the axis of the liner andelongated to eliminate as far as possible the danger of collapse orbreaking of the pipe becausey of the perforations, due to pressure ofthe gas and oil in the well, it having been found by experiment thatthis arrangement permits maximum passages for the liquid at a minimum ofwea-kening lof the pipes.

The pipes 3 are threadedly connected t0- gether as shown at 6. The upperend of the liner is closed by the head 7 having threaded engagementywith the upper end of the inner pipe 2 of the top unit, and the lowerend of the liner is closed by the cap 8 having threaded engagement withthe lower end of the `outer pipe 3 of the bottom unit.

The ends of the inner pipes 2 are provided with tapered collars 9 whichwill conine a heave-in of sand to one unit of the liner which willreta-in the string of inner pipes 2 in spaced relation to the string ofyouter pipes 3 and which are slightly spaced at their larger ends fromthe string of outer pipes 3 to permit the oil to pass from one unit ofthe liner to another. Certain of the collars 9 are internally screwthreaded to receive externally screw threaded hollow extensions l0 oncertain of the other collars whereby to connect the adj acent ends ofthe inner pipes 2. The lower end vof the bottom inner pipe 2 is closedby a cap 11 having threaded engagement with the collar 9 at said end lofsaid pipe, and the upper end of the top inner pipe 2 is closed by thehead 7.

rihe head 7 is larger in vdiameter than the external diameter of theliner, and is provided with a depending stem 12 which is threaded in theupper end of the top inner pipe 2. rlhe head 7 is located in the lowerend portion of the well casing 13, and a gasket 14 of rubber or othersuitable material establishes a liquid-tight connection between the headand well casing. in its upper side the head 7 is provided with a conicalrecess 15 in which a removable plug 16 is positioned. A conical gasket17 of rubber or other suitable material is located between the plug 16and the wall of the recess 15. The head 7 is also provided with an axialopening 1S which registers with an axial opening 19 in the plug 16. rlhelower end of a well tubing 2O is threaded in the opening 19 of the plug16, and extends from said plug to and through the casing head of thewell. If desired the well tubing 2O may extend below the liner head 7and to attain this end a tubing 20 is threaded at its upper end in theopening 19 of the plug 15 and passes downwardly into the liner throughthe opening 18 of the head 7.

The liner may be readily positioned for use by first inserting thestring of outer pipes 3 in the well, and nei-it inserting the string ofinner pipes 2 in the string of outer pipes 3, and by next inserting theplug 16 in the recess 15 of the head 7 which last named step may bereadily performed after securing .the plug to the well tubing 2O and byemploying the well tubing as a guide for directing the plug 16 into therecess 15. The oil flo-ws through the outer pipes 3 into the inner pipes2 and thence through the well tubing 20. lf the oil does not flownaturally a pump may be connected to the well tubing 20. As the linercannot be weakened by the action of the sand on the openings l and 5thereof, there is no danger of the same collapsing. Furthermore theliner cannot become clogged for the reason that sand bridges cannot formtherein. The opening 18 in the head 17 is larger diametrically than thetubing 2Oa so as to permit the tubing to be freely passed through thehead. This opening is screw threaded to permit a fishing string of lightdrill pipe to be screwed into the head 7 if at any time it is necessaryto pull the inner liner pipe from the well.

It should be understood that the drawing is merely illustrative and doesnot pretend to give exact proportions. Furthermore, the said drawing isillustrative of a preferred construction7 it being my expectation thatvarious changes and modifications may be made without departing from thespirit and scope of the invention.

What is claimed is:

1. An oil well liner unit comprising relatively spaced inner and outerpipes provided with perforations the perforations of one pipe beinglocated in the upper half thereof and the perforations of the other pipebeing located in the lower half thereof.

2. An oil well liner unit comprising inner and outer pipes provided withperforations, the openings of the inner pipe being located in the lowerhalf thereof, and the perforations of the outer pipe being located inthe upper half thereof.

3. An oil well liner comprising relatively spaced inner and outer pipesprovided with perforations, the perforations of the respective pipesbeing at opposite ends thereof and out of registration and arranged atan angle to the axis of the liner, all of the perforations in each pipebeing inclined in the same general direction.

4. An oil well liner comprising a string of outer pipes provided withperforations,and a string of inner pipes provided with perforations andtapered portions on the outer surface thereof.

5. An oil well liner comprising a string of outer pipes provided withperforations, and a string of inner pipes provided with perforations andprovided at their meeting ends and on the outer surfaces thereof withoppositely tapered enlargements.

6. An oil well liner comprising inner and outer pipes provided withnonaegistfering perforations, a closure for the lower end ot' the outerpipe, a closure for the lower end of the inner pipe, relatively .spacedtapered enlargements on the inner pipe, and a head for the upper end ofthe liner.

In testimony whereof I affix my signature.

JOHN TWEEDDALE.

